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F. J. HUBBARD. DENLTAL BRACKET.

No. 248,319. Patented Oct. 18,1881;

' 7' r 50 7" 74 Z'ne ss 9; "Tia n we 70 UNITED STATES PATENT OFFICE.

FREDERIU J. HUBBARD, OF CHICAGO, ILLINOIS, ASSIGNOR TO ABNER B. THOMAS AND BARTON SEWELL, OF SAME PLACE.

DENTAL BRACKET.

SPECIFICATION forming part of Letters Patent No. 248,319, dated October 18, 1881,

Application filed January 31, 1881. (No model.)

To all whom it may concern:

Be it known that I, FREDERIG J. HUBBARD, a citizen of the United States, residing at Ohicago, in the county of Cook and State ofIllinois, have invented a newand useful Dental Bracket, of which the following is a specification.

My invention relates to improvements in dental brackets in which the vertical pivot upon which. the entire bracket has its horizon-' anism illustrated in the accompanying draw-' ings, in which Figure 1 represents a side elevation of a bracket embodying my invention; Fig. 2, a perspective of the front end of the same, with a part of the plate a broken away to show bolt e, nut e, and the segmental arm; Fig. 3, a similar view, taken from the opposite side of the forward end of the bracket; and Fig. 4, a vertical section through the plates 1 a, with the bolt shown in full lines and the handle partially broken away.

Similar letters of reference indicate the same parts in the several figures of the drawings.

A represents the pivot upon which the bracket swings horizontally, said pivot having its bearings in a suitable bracket-plate secured to the wall of the room or to the cabinet of the operator.

B B are parallel bracket-arms, pivoted at theirinner ends to the pivot A and at their outer ends between two links or clamping plates, a a, so that they may have a vertical movement without destroying their parallel- Cast with or otherwise secured to the upper end of the link a is a bracket or guide, 1), provided with a set-screw, b, and adapted to carry a horizontally-sliding arm, 0, supporting on its outer end, at c, the tray or table of the operator.

Arm B is provided upon its outer end with a stud, 61, extending some distance from the links a a, and forming a bearing for a pivoted segmental rod,D,which passes throughatransverse bolt, 0, in the links a a,which bolt is transversely perforated to receive the rod, and is slightly beveled at one end, and at its opposite end screw-threaded to receive a nut or tightening-handle, E.

Loosely secured upon the bolt 6 is a cone or other shaped clamping washer or plate, 0, provided at its apex with a groove corresponding with the segmental rod, which moves in and is held. between the walls of the groove and the opposite wall of the perforation in the bolt, as will now be explained.

The bolt 0 has a longitudinal movement in its bearings in the links when screwing up or unscrewing the handle E, but is held firmly when the handle is screwed down against the link a, at which time the washer 0 comes in contact with plate a, and the segmental rod is thus held fast between the washer and the opposite wall of the perforation in the bolt.

It will be observed that as the outer ends of the bracket-arm B'B move in an arc of a circle, it is necessary that, in order to use a rod clamped in the above manner to maintain the bracket-arms at the desired adjustment, such rod should also move in the arc of a circle, but

. 1. The combination, with the pivoted bracket arms, the links connecting their outer ends,

a perforated bolt, and a locking-nut upon said bolt, of a segmental rod pivoted upon the end of one of said arms and passing through and adjustably held in the perforated bolt, substantiall y as described.

2. The combination, with the bracket-arms B B and links a a, of the segmental rod D,

perforated screw-threaded holte, receiving said f0I2Ll56d bolt e, receiving said rod, cone-washer, rod, tightening nnt or handle E, and a clamp- I c, and tightening-handle E, substantially as ing-washer, e, as and for the purpose set forth. and for the purpose described.

3. The combination, with the horizontally FREDERIG J. HUBBARD. 5 and vertically swinging parallel bracket-arms Witnesses:

B B and the horizontally-sliding arm 0, sup- JNO. G.-ELLI01T, porting the table, of the segmental rod D per- WILLIAM C. WRITING. 

